Erosion Control March/April 2017 : Page 42

On the Ground and Underground Geosynthetics shore up progress. BY DAVID C. RICHARDSON A lot of good things have been said about Frank R. Bowerman Landfill in Orange County, CA. It has recently powered up a major methane-to-electrical generation station to capture and reuse landfill gasses that some waste operations would be content just to burn off as waste. According to Robert Sjoquist, president of Soils Solutions Inc., the landfill also has a “very aggressive recycling operation.” He says the facility welcomes almost every kind of waste. And most impressive, he says, “They are very people centric.” In addition to clean-up days in the surrounding neighborhood, the landfill is interac-tive with the community, welcoming visitors who would like to come by and better understand the landfill’s programs and operations. “It’s a very forward-thinking facility,” says Sjoquist. Kevin Hanson of Orange County Waste and Recycling says he is proud that the facility has been recognized as one of the best landfills in the US, and he also notes it is one of the top facili-ties in terms of tonnage accepted per day. Nonetheless, says Hanson, the one thing consistent with all landfills is change. Adding methane production and electri-cal generation to Bowerman Landfill’s operations ushered in big change on the positive side, but in addition, he notes, “We constantly have new regulations coming up and we have to keep on top of them.” There is constant change in the physical realm of a landfill as well. Much of that change revolves around the effects of gravity on the movement of land and water. Hanson says two of the most challenging ongoing and continuous changes at Bowerman Landfill, or any landfill, involve this movement of land and water. Depressed Over Trash “We found we had serious differential settlement issues where soil is either on top of native soil or on top of trash,” explains Hanson. Although, he says operators may have a rough idea where the buried trash is, the exact location often doesn’t become clear until “what used to be a slope” gets flattened out into “a depression” by the force of decomposition and gravity working variably on soil and buried trash. When that happens, any infrastructure situated on the collapsing earth is subject to deformation and fracture. In this way, differential settle-ment doesn’t just threaten to expose trash, it also interferes Top: Before installation of Concrete Cloth Above: Ditch with CC8 veneer with efficient drainage. According to Hanson, this settlement can become a major problem when it begins to affect drainage infrastructure. Concrete-faced drainage ditches on the surface of Bowerman Landfill, designed to carry stormwater runoff, had been displaced by differential settlement along the slopes. There was the potential that cracks and voids appearing at junctions and fractures in the trapezoidal concrete drains could be undermined during heavy rains, says Hanson. “Water WWW.EROSIONCONTROL.COM 42 EROSION CONTROL PHOTOS: ORANGE COUNTY WASTE AND RECYCLING